I am working through Binary IO with objects and am running into a curious error.
The program executes perfectly until it hits the very end. At "return 0", the program fails. The debugger picks up SIGABRT when executing "return 0". This seems to me to indicate a deconstructor problem of some kind. However, I can't seem to find any deconstructor problems (I am fairly new at programming though).
then the program finishes exiting without error . . . . but the whole point is to be able to read from the binary file. With those two lines in the code, the program successfully reads from the file and outputs the objects to the console ,but fails at "return 0";
Here is the code:
#include <iostream>
#include <fstream>
#include "Student.h"
using namespace std;
I am currently trying to understand why this example for using an array as an argument in a function has a different result than what the lecture notes say it should be.
So supposedly sum should return with the value 28, but I get 27 no matter what. I also am not very good at reading and understanding what exactly the order of operations for this function are.
Code: #include <iostream> using namespace std;
int sum(const int array[], const int length) { long sum = 0; for (int i = 0; i < length; sum += array[++i]); return sum;
I'm getting unexpected output in 2 different cases. The 1st deals with bitfields. The C++ standard has this line about integral promotions:
An rvalue for an integral bit-field (9.6) can be converted to an rvalue of type int if int can represent all the values of the bit-field; otherwise, it can be converted to unsigned int if unsigned int can represent all the values of the bit-field.
If the bit-field is larger yet, no integral promotion applies to it. If the bit-field has an enumerated type, it is treated as any other value of that type for promotion purposes.
This sounds like the value of a bitfield will always be treated as a signed int if the signed representation of the value will fit in the bits. This seems to hold true for my C compiler, but not my C++ compiler.
I tried storing a small negative value in a bitfield that has enough bits to store the sign bit and the value. But when I print out the bitfield, I always get a large number
The other issue I'm having is sort of similar. I'm trying to store 4294967295 into a float, but when I print it out, I get 4294967296. i've tried storing a few other large values like this and what's printed out is rarely the value I stored. I thought it might be because of some int to float conversion, so I tried 4294967295.0. Still no luck. Then I remember that defaults to a double so maybe that's the issue so I tried 4294967295.0f. Still no luck. Why can't I store the correct value here? I don't think it's an IEE format thing since I can use these values as floats on a calculator program.
The example code showing both issues is below.
Code: #include <stdio.h> typedef struct { signed char x : 5; signed char y : 3; }my_struct_t;
My compiler (GCC) keeps expecting an expression where it shouldn't in 1 specific piece of my code:
int zxcNewWindow( HWND parent, TCHAR *text, zxWINDOW *kid, UINT style, int x, int y, int w, int h, int type ) // right here { *kid = zxDefWINDOW;
The project contains only 2 files right now and the settings are just the default for an empty Code::Blocks 12.11 project. Both files are in UTF-8 format (tried in ASCII too), I just cannot see why this is not compiling correctly. I'll post the files in the next two posts.
Edit: For those of you who didn't get what the error was from the above here's the full log:
mingw32-gcc.exe -Wall -g -DzxDEBUG -c C:MePrjscppzxGUImain.c -o objmain.o C:MePrjscppzxGUImain.c: In function 'zxcNewWindow': C:MePrjscppzxGUImain.c:39:10: error: expected expression before '{' token Process terminated with status 1 (0 minutes, 0 seconds) 1 errors, 0 warnings (0 minutes, 0 seconds)
I'm just starting c++, doing tutorials. So many tutorials. I've noticed that the tutorials all assume the same thing: That the user will always do exactly as he/she is told when asked for input.
Example: "Please enter your age:"
Now, the example code might be expecting the user to type some numbers, but what if the user feels like typing out the letters of their age?
"I am ninety five thank you very much, sonny"
I could specify to the user that I only want the information in number form, but what if the user is just being a dick?
What if the user types, "none o' yer business."?
So... how to approach "fool-proofing" player input?
I keep getting a segmentation error when ever I have the following code...
int main(void) { //Section 1 unsigned long val = 12; std::vector<unsigned long> vval; for(unsigned long i = 0; i < 100; ++i) { vval.push_back((unsigned long)0);
I have a WordRecord that contains a LinkedList (both my doing). I have rigorously tested my LinkedList class, and know that it works (heck, I used it in the last project I had!). The problem is that undefined behaviour seems to happen when using the WordRecord, which has a std::string and a LinkedList<unsigned>. (The problem happens with the LinkedList.)
Here is the code:
main.cpp #include <iostream> #include "BinaryTreeNode.h" // here for test purposes #include "LexicographicTree.h" #include "LinkedList.h"//also for test purposes #include "OutputStream.h" #include "WordRecord.h" using namespace std; int main() { // setup the OutputStream to print to "test.txt" OutputStream stream("test.txt"); // create a sampleWordRecord (make it have the word "I" on line 1)
[code]....
One of the requirements for the project is that it must compile on Unix server (I am using Windows, and have tested it in both environments.) I get a core-dump in the Unix environment. On the other hand, the output on-screen in the Windows environment looks right. However, when I open up the text file, I get the following
Sample word record:
WordLines I{14} /* I have no what is happening to sampleWordRecord's LinkedList; I am not trying to modify it, except for where I created the sampleWordRecord! */
So the latest challenge from jumping into c++ is as following.
Code: Write a function that builds the multiplication table of arbitrary dimensions This chapter also talks a ton about 2d arrays.
So I've built my program thus far as this.
Code: #include <iostream> using namespace std; int drawTable(int,int); int main()
[Code] .....
So basically, the idea is that I can use the arrays dimensions as a placeholder, and just multiple them to get that specific spot, so table[0][0] = 0, [0][1] = 0 and so on. However the output actually seems to be randomly generated numbers so I'd like to ask, what am I doing wrong? Am I on the right track? Or have I missed the bus stop completely.
I predicted the outcome as being 01230 as I thought the prefix decrement operator on iterator ce would prevent the final element of the list from being transformed.
I was wrong, the correct output is 01234.
So, I removed the decrement prefix and ran the test again, expecting a different result. It wasn't! The result was still 01234.
Only when I decremented ce twice did I get the result I initially expected, 01230.
why the first decrement of ce appears to have no effect?
My Windows service may download a binary update in the background using WinHTTP APIs. I'm using code similar to the one from the bottom of this MSDN page. For ease of access I'll copy if below:
The issue I'm experiencing is that while downloading, the code above "hogs" most of the bandwidth available on the client computer. My goal is to make it "throttle" itself on a configurable "bps" level, say at 50 kbps and not use any more bandwidth.
Someone suggested measuring my current download speed (in bps) and depending on the value make the thread "sleep" before calling WinHttpReadData again.
Code: DWORD DesiredBitsPerSec = 50 * 1000;//for 50 kbps if(fBps > DesiredBitsPerSec) { DWORD dwW = (DWORD)((fBps - DesiredBitsPerSec) * 1000) / DesiredBitsPerSec; if(dwW > 0) ::Sleep(dwW);//Sleep to throttle the download speed to the one we need }
So I implemented it into the code above but it didn't work -- the Sleep API would produce very strange delays. So I decided to add a little bit more tracking code to actually be able to see what BPS values I'm getting.
I created a small test project that is attached to this post to illustrate the issue. (It's hard to explain without running an example.)
For a test I began downloading a large binary file (Windows 10 MSI, off Microsoft's server) and at the same time had the Task Manager open on a Performance tab that was showing me the current network throughput. I made a screenshot:
But as you can see, the reading on the test program and the actual network BPS values differ greatly.
I'm writing some functions pertaining to binary trees. I've used recursion once before while learning quicksort but am still quite new and unfamiliar with it. And this is my first time touching a binary tree. So my question: In my addnode function, will the return root statement at the end ever return a value other than the value passed to the function?
#include <iostream> using namespace std; int n; int& test();
[Code] ....
Explanation
In program above, the return type of function test() is int&. Hence this function returns by reference. The return statement is return n; but unlike return by value. This statement doesn't return value of n, instead it returns variable n itself.
Then the variable n is assigned to the left side of code test() = 5; and value of n is displayed.
I don't quite understand the bold sentence. Shouldn't value of n and variable n be the same?
In my program below, in the getage and get level functions, if an incorrect input is entered, then the correct one is entered after, it still returns the bad input back to main.
myClass is a class I have. Now, in the class, I have a function what_value and I need to get the classes.at(0) from the pointer to it in another function. But the problem is, how can I do it? I'm completely stumped, here's what I thought of:
newClass.*myclass.what_value();
And it I get an error from the compiler. Basically, how can I do this in another function with a pointer:
I'm going to write a program that takes string until end of file(eof). An condition must be considered and that is it must also terminate by a new line. For example when it's prompting me to enter a string if I press enter it must terminate and exit the program. How is it possible? I tried saving carriage return("") as a string then I compared it with the entered string but it didn't work.
